Self referential has many through - belong to association dows not work?

Rails
1

I’m trying to set up a self-referential relationship, as described in
this great video -

  • and it’s mostly working, but not entirely.

My self-referential relationship describes relationships between
people using the foreign keys person and related_person in class
Relationship both associating to the class Person

My problem is that when I update related_person_id for a specific
relationship the associated object relationship.related_person is not
updated. Related_person_id in relationship has an updated value,
while relationship.related_person.id has the old value.
What is wrong in my declarations ??
They are as follows

Class Person

has_many :relationships, :dependent=>:destroy,
:autosave=>true
has_many :people, :through
=> :relationships, :source=>:person, :uniq=>true
has_many :related_people, :through
=> :relationships, :source=>:related_person, :uniq=>true

Class Relationship
belongs_to :person
belongs_to :related_person, :class_name => ‘Person’,:foreign_key
=>‘related_person_id’

Table relationships
class CreateRelationships < ActiveRecord::Migration
def self.up
create_table :relationships do |t|
t.integer :person_id, :default=> nil
t.integer :related_person_id, :default=> nil
t.string :person_role, :limit=>80
t.string :related_person_role, :limit=>80
t.integer :family_id, :default=> nil
t.integer :event_id, :default=> nil
t.integer :user_id, :default=> nil
t.integer :archive_id, :default=> nil
t.timestamps
end
add_index :relationships, :person_id
add_index :relationships, :related_person_id
add_index :relationships, :archive_id
add_index :relationships, :person_role, :index =>
true
add_index :relationships, :related_person_role, :index => true
end

2

Hans <Hans.Marmolin@…> writes:

I’m trying to set up a self-referential relationship, as described in
this great video - #163 Self-Referential Association - RailsCasts
association
What is wrong in my declarations ??
Class Relationship
belongs_to :person
belongs_to :related_person, :class_name => ‘Person’,:foreign_key
=>‘related_person_id’

The code looks OK to me. Are you sure it’s not a caching/stale record
problem? Fire up a console and execute your code manually. If you see
the
same error try reloading the instance, eg:

person.reload

This will ensure you are looking at a current version from the database
rather
than a (possibly) stale version in Ruby memory.

3

On Jun 21, 4:27am, Hans [email protected] wrote:

updated. Related_person_id in relationship has an updated value,
while relationship.related_person.id has the old value.
What is wrong in my declarations ??

Nothing, but updating the related_person_id field is the problem.
You’ll typically want to update the relationship with an object
(assigning to related_person).

–Matt J.

4

Thanks for the advices

Matt do you mean that I should use
relationship.related_person=Person.new instead of changing the foreign
key directly
If so, is that a general requirement when updating foreign keys ?

Andrew
How do I avoid the caching/stale record process
I have tried to make an extra save for all involved object but did not
change anything

5

Hans <Hans.Marmolin@…> writes:

Thanks for the advices

Matt do you mean that I should use
relationship.related_person=Person.new instead of changing the foreign
key directly
If so, is that a general requirement when updating foreign keys ?

I think he means:

person = Person.first
other_person = Person.last
person.relationships << other_person

or

person.relationships << Person.new

or even better

person.relationships << Person.create(params[:person])

Andrew
How do I avoid the caching/stale record process
I have tried to make an extra save for all involved object but did not
change anything

Stale objects can be a fickle affair and there are no magic bullets.
Sorry.